Bank segment - Allowance for credit losses (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Allowance for credit losses:
Beginning balance	$ 67,211	$ 91,793	$ 71,130	$ 101,201
Charge-offs	(1,517)	(2,260)	(3,075)	(5,941)
Recoveries	1,505	1,676	2,907	2,984
Provision for credit losses	2,257	(12,957)	(1,506)	(19,992)
Ending balance	69,456	78,252	69,456	78,252
Real estate \| Residential 1-4 family
Allowance for credit losses:
Beginning balance	7,874	5,261	6,545	4,600
Charge-offs	0	(20)	0	(20)
Recoveries	3	51	11	54
Provision for credit losses	643	226	1,964	884
Ending balance	8,520	5,518	8,520	5,518
Real estate \| Commercial real estate
Allowance for credit losses:
Beginning balance	20,176	34,345	24,696	35,607
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provision for credit losses	724	(5,637)	(3,796)	(6,899)
Ending balance	20,900	28,708	20,900	28,708
Real estate \| Home equity line of credit
Allowance for credit losses:
Beginning balance	5,650	5,901	5,657	6,813
Charge-offs	0	10	0	(40)
Recoveries	31	61	42	76
Provision for credit losses	415	(637)	397	(1,514)
Ending balance	6,096	5,335	6,096	5,335
Real estate \| Residential land
Allowance for credit losses:
Beginning balance	697	573	646	609
Charge-offs	0	0	0	0
Recoveries	96	11	101	21
Provision for credit losses	(116)	34	(70)	(12)
Ending balance	677	618	677	618
Real estate \| Commercial construction
Allowance for credit losses:
Beginning balance	2,340	1,453	2,186	4,149
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provision for credit losses	294	176	448	(2,520)
Ending balance	2,634	1,629	2,634	1,629
Real estate \| Residential construction
Allowance for credit losses:
Beginning balance	31	16	18	11
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provision for credit losses	15	0	28	5
Ending balance	46	16	46	16
Commercial
Allowance for credit losses:
Beginning balance	14,314	24,504	15,798	25,462
Charge-offs	(148)	(319)	(224)	(1,090)
Recoveries	399	366	752	639
Provision for credit losses	(2,152)	(4,493)	(3,913)	(4,953)
Ending balance	12,413	20,058	12,413	20,058
Consumer
Allowance for credit losses:
Beginning balance	16,129	19,740	15,584	23,950
Charge-offs	(1,369)	(1,931)	(2,851)	(4,791)
Recoveries	976	1,187	2,001	2,194
Provision for credit losses	2,434	(2,626)	3,436	(4,983)
Ending balance	$ 18,170	$ 16,370	$ 18,170	$ 16,370

Amount excluding accrued interest, of allowance for credit loss on financing receivable. Excludes net investment in lease.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 45
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=124255206&loc=SL82895884-210446

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

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- Definition

Amount, excluding accrued interest, of increase in allowance for credit loss on financing receivable from recovery. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 13
-Subparagraph (e)
-URI https://asc.fasb.org/extlink&oid=124255953&loc=SL82919249-210447

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- Definition

Amount, excluding accrued interest, of decrease in allowance for credit loss on financing receivable from writeoff. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 13
-Subparagraph (d)
-URI https://asc.fasb.org/extlink&oid=124255953&loc=SL82919249-210447

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- Definition

Amount, excluding accrued interest, of credit loss expense (reversal of expense) on financing receivable. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 13
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=124255953&loc=SL82919249-210447

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